Regexp backslash consistency.

Every backslash in the regexp string was escaped except for the ones before a `$`. Consistency helps transplant this regexp into other languages -- i.e. my user script.

For Python, I believe none of backslashes need escaping in these regexs anyway. To demonstrate,

```python
r"\(" == "\\("  # => true
 "\(" == "\\("  # => true
```

Even if it was needed you could avoid it by using a raw string syntax, `r""`.